EEV. A. E. EATO^S' ON RECENT EPHEMEEID^ OR MATPLIES. 23 



nerviu'e (8) at tlie wing-roots, the second (9-) ending apart from it in the regular raised 

 axillary fold or vessel ; wiug-membrane translucent and dull. Pronotum large, trans- 

 verse, broader than the head, tumescent, arched behind. Setae pubescent or minutely 

 pilose, short in ? , very long and divaricate in d . Forceps borne upon a deflexible 

 laminar lobe prolonged from the distal ventral margin of the 9th segment, which is not 

 represented in the ? , the proximal joints of the limbs the longest. Lobes of the penis 

 unarmed ; orifice of the seminal duct subapical, and on the inner side of the lobe. Eyes 

 of the 6 large, oval, narrowly separated from each other ; anterior ocellus much smaller 

 than the hinder two. Pore tibia and tarsus densely rugose transversely ; ungues in 

 each tarsus unequal, and not quite alike. Nymph fossorial ; the labium concave, its 

 sides approximated to each other above ; the tracheal branchiae borne upon protuberances 

 armed with single minute spinules, situated in or near the middle of the sides of their 

 respective segments, and arched upwards over the dorsum ; the hinder lateral angles of 

 the segments not produced backwards. Pore legs stout, densely bearded with long hair 

 on the femur and tibia ; the tibia and tarsus compressed, the former oblique at the tip. 

 Terminal margin of the fore wings free. 



The single genus contained in this subsection is a composite one ; but further materials 

 are needed to enable the incongruous species to be completely dissociated from the type. 

 They may be referred provisionally to three subgenera: — JPalingenia (typical), Burmeister, 

 containing European and Western Asiatic species ; Anagenesia, containing Indo-Malay, 

 and a Siberian species ; and a nameless subgenus containing Brazilian species. 



PALINGENIA, Burm. 1839; restricted Eaton, 1868. 



Illustrations. Adult (details) PI. I. & III. 1 «-!/ (whole figures), see citations under 

 P. longicauda. Nymph PI. XXV., see also citations of Swam., Gorove, and especially 

 Corn. (18-18) under P. longicauda (whole figures and details). 



Subgenus Palingexia (typical). 



Adult.— Vrcohv^chivil nervure (6) of the fore wing forked beyond the middle ; two con- 

 spicuous sets of longitudinal nervures proceed in pairs to the terminal margin (at 4<\ and 

 at 5 & 6). Pore tarsus of 6 about twice and a half (2f ) as long as the femur. Seta3 2, 

 in the 6 upwards of three times as long as the body, in ? about the same length as 

 the body. Anterior thoracic spiracle gaping, large ; aperture bivalvular, the lower 

 valve the smaller, with concave margin ; the upper valve sinuous, having a large salient 

 obtusely rounded lobe projecting inwards in front of the tegulae. Orifice of the posterior 

 thoracic spiracle gaping, irregularly reniform with the siniis in front. 



Nymph, [after Cornelius].— Six pairs of abdominal tracheal branchiae, each lamina 

 fringed with short simple fibrils, and perhaps folded together lengthwise. Seta? about I 

 as long as the body in the female. 



DistriJjut/ou. Eastern N. temperate region. 



Tyjye. P. longicauda (in Ephemera), 01. 



Etymology, TraXiyyeveu, in allusion to its annual swarming. 



